The core part of a helicopter is the main rotor. With its two and more blades hinged on a rotor head and supported for pivotal movement about their longitudinal axes, to provide lift and propulsion. To produce or increase thrust for the lift, the pitch of the rotor blades is adjusted collectively, that is, synchronously. The lift of the aircraft is produced by increasing the thrust vector of the blades with the aid of a control which synchronously alters the pitch of the rotor blades.
The helicopter pilot controls the rotor blades by a swash plate comprising a rotary axially movable and tiltable part, supported by radial and axial bearings on a stationary part mounted to a gear housing, which by so called scissors controls the pitch of the blades, the blades being driven by a rotor mast. The rotary part is secured to the rotor head by another set of a scissors.
The movement of the swash plate is transmitted, via a lever mechanism, to the blade connections located at the rotor blade input correction before or behind the blade fixtures, in a manner such that the angle of incidence of the rotor blade increases or decreases with the adjustment of the swash plate.
For a flying manoeuvre, the helicopter pilot adjusts the swash plate by a single lever mechanism. In progressive rotor systems, parallel to said mechanism are disposed hydraulic servomotors which, on one hand, facilitate the control and, on the other, make possible a superimposed regulation, which counteracts the rotor blade oscillations that otherwise occur. To this end, hydraulic servomotors and active hydraulic dampers which are situated in the rotating system, individually control separate rotor blades.
One or more gas turbines drive the main rotor, via a gear and a main rotor mast, which is rotatably supported in the gear housing and on which is fixed the rotor head.
The hydraulic servomotors and active hydraulic dampers need hydraulic power of about 1% of the main rotor power. Separate pumps are used for this. These have a considerable weight and demand substantial installation space. In addition, the feed-in lines to the servomotors are often long and complex, especially when they pass from a stationary part to a rotary part.
The problem, on which the invention is based, is to supply the hydraulic motors and active dampers with the required power, to save weight, to reduce construction costs and to improve efficiency.